Abstract: A mixing apparatus, e.g. for making concrete, has a triangular base supporting a rotatable or nonrotatable, upwardly open cylindrical drum as well as a main shaft carrying a large sprocket wheel which is linked by a chain with a smaller sprocket wheel on an auxiliary shaft journaled on one of the sides of the triangle. A motor mounted on another side of the base drives the auxiliary shaft via a speed-reducing belt transmission. The main shaft and/or an extension thereof above the drum carries ancillary force-transmitting members such as a reel or a sprocket for the selective operation of external accessories, e.g. a shovel, a hoist, or a force pump. Bulk material in the drum is agitated by a set of relatively rotating blades which may be driven by the main shaft or by a separate motor.